Patejmf of



R. JARDINE. METHOD OF MAKING VALVE TAPPET'S.

APPLICATION HLED"1AY 18,-1920.

Patented Nov 21 1922,

Patented Nov. ai, 1922.

UNITED STATES I i,aaeea5 PATENT ensues.

ROBERT JARDINE, OF CHICAGO, ILLINOIS, ASSIGNOR 'IO RICH TOOL COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

METHOD OF MAKING VALVE TAPPETS.

Application filed May 18,

To all whom it may concern:

Be it known that I, ROBERT JARDINE, a citizen of the United States of America, and resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Methods of Making Valve Tappets, of which the following is a specification, and which-are illustrated in the accompanying drawings, forming a part thereof.

The invention relates to the manufacture of valve tappets for internal combustion engines, and has as an object the provision of a method of producing such article, in a form which will be light, and str0ng, but of inexpensive construction when made by the improved method.

In the accompanying drawings- Fig. 1 is an elevation, part y broken away, of a partially completed tappet illustrating a form produced by the initial steps of the process;

Fig 2 is a in Fig. 1;

Fig. 3 is an elevation, partly broken away, of a completed tappet;

Fig. 4 is a plan view of the structure shown in'Fig. 3;

Fig. 5 is a longitudinal sectional view, partly in elevation, showing a mod fied form of tappet and parts of an engine wlth which it is associated; and

Fig. 6 is a similar view showing a further modification in the form of the completed tappet.

The valves of an internal combusion engine, and the tappets for actuating them,

must be raised and lowered many times per minute. Any excess of weight in such rapidly reciprocating parts is a serious matter, it being important to have the valves open as nearly instantaneously as posslble and close in the same manner, that the total time of full opening may be as long as possible. To secure this action with a heavy art not only requires: a very stiff spring or closing the valve, which means excessive wear on the cam, but the momentum of the rapidly moving valve striking its seat causes se Vere blows upon the seat.

In the'improved tappet lightness is secured by giving the body 10 tubular form, a suitable head, as 11, for cooperating with a cam, being provided at one end of the tube. In -Figs. 3 and 5 thetappet is shown plan view of the structure shown 1920. Serial. No. 382,312.

as of the mushroom type, the head having a plane bearing face for engagement by a lifting cam 11. shown in Fig. 6, the bearing end of the tappet is provided with a roller 11 for engagement with the cam. The specific form of the bearing end is 'not' of importance iii connection with the present invention.

Ample strength may be obtained by the use of thin walls for the body of. the tappet, but in order to provide a suitable connection or seat upon the upper end of the tappet for In the construction the valve stem or intermediate element conform the threads,'while maintaining the unithe desirable lightness of so muc of the walls of this body as is .not required to be threaded, the body is made with two internal diameters, that of the portion adnecessary thickness of metal in which to form exterior diameter of the bod 10 and jacent its upper or open end being less than that of the remainder of the body.

In the production of such a tappet, shown in the several completed forms, the article I isv first given the form shown in Fig. 1, the

upper portion 13 being of greater external diameter than the remainder of the body 10, and the bore 14, formed by the use of a drill,

is of uniform diameter and extends substantially to the lower end bearing the head 11. The portion 13 is then compressed radially by a suitable operation, such as swaging, forcing the, metal inward and thus reducing the internal diameter. That is to say, in the blank as represented in Figs. 1 and 2, the upper end of the tappet bulges outwardly, While in the finished article, as in Figsf 3, 4, 5 and 6, it bulges inwardly.

The increased thickness of the walls of the portionl3 over that of the remaining portion of the body of the tappet will depend upon the character of the seat to be provided for the connecting element. lVhen this seat in Fig. 3, to receive a connecting rod 13,

this increased thickness may not be of great extent, and a verylight tappet, having nevertheless, ample strength, is provided.

' \Vhen a small connecting rod is employed,

as in Fig. 6, this thickening of the wall is somewhat greater.

,If the character of theconnection demands a greater mass of metalat the upper end of th tappet, as in the form shown in Fig; 5, where the connecting element 13 is in the form of a rod loosely seated in a counterbore of the tappet, such mass may be provided in the manner. described without seriously increasing the weight, the integral construction of th body insuring ample strength. 4

I claim as my invention- The method of producing a valve tappet remote from the said head drilling'the stem. I

portion of the blank to form a bore therein of uniform diameter extending throughout the length of the stem compressing the larger outer end portion of the stem to a diameter uniform with that part of the stem adjacent the head whereby thediameter of the bore of: the stem is reducedin the outer end portionbf th stem and forming that part of the inner Wall of the stem which is of reduced diameter for attachment to a connecting rod or the like.

1 ROBERT IJARDINE. 

